　　 Solar energy is the most direct and most common and cleanest energy on the earth. As a huge amount of renewable energy, solar energy reaches the surface of the earth. The radiant energy is about 250 million barrels of oil per day. It can be said that it is inexhaustible and not used. exhaust. The spectrum of LED is almost entirely concentrated in the visible light band, so the luminous efficiency is high. Most people think that energy saving lamps can save 4/5 energy is a great initiative, but LEDs are more energy-saving than energy-saving lamps, which is a greater solid-state light source. reform.
Solar LED lighting integrates the advantages of solar and LED.
1, system introduction
1.1 Introduction to the basic components of the system
Solar battery
A battery is a device for energy conversion and storage that converts chemical or physical energy into electrical energy. A battery is a kind of chemical power source. It consists of two different compositions of electrochemically active electrodes, which are composed of positive and negative poles soaked to provide media conduction. When connected to an external carrier, the internal chemistry is converted. Can provide power. The component parts (including the bracket), the LED lamp head, the control box (with controller, battery) and the lamp pole are composed; the solar panel has a luminous efficiency of 127 Wp/m2, and the efficiency is high, which is very advantageous for the wind-resistant design of the system; The lamp head portion is a planar light source with a 1W white LED and a 1W yellow LED integrated on a printed circuit board and arranged at a certain pitch.
The control box body is made of stainless steel, which is beautiful and durable. The maintenance-free lead-acid battery and charge and discharge controller are placed in the control box. This system uses valve-regulated sealed lead-acid battery. Because it has little maintenance, it is also called “maintenance-free batteryâ€, which is conducive to the reduction of system maintenance cost. The charge and discharge controller is designed with both functions in mind (with light) Control, time control, overcharge protection, over discharge protection and reverse connection protection, etc.) and cost control, achieving high cost performance.
1.2 Introduction to working principle
The working principle of the system is simple. The solar cell made by the solar photovoltaic effect principle receives solar radiant energy and converts it into electric energy output. The battery is stored in the battery through the charge and discharge controller. At night, the illuminance gradually decreases to about 101ux, and the solar cell The open circuit voltage of the board is about 4.5V. After the charge and discharge controller detects this voltage value, the battery is discharged to the lamp head. After the battery is discharged for 8.5 hours, the charge and discharge controller operates and the battery discharge ends. The main function of the charge and discharge controller is to protect the battery.
2, system design ideas
The design of solar street lights is basically the same as that of general solar lighting, but there are more links to consider. The following is an example of the solar LED high-power street light from Hong Kong Zhen Mingli Group Co., Ltd., which is analyzed in several aspects.
2.1 Solar cell component selection
Design requirements: Guangzhou area, load input voltage 24V power consumption 34.5W, working hours 8.5H per day, to ensure continuous rainy days 7 days.
(1) The average annual radiation dose in Guangzhou in the past 20 years is 107.7Kcal/cm2, and the peak sunshine hours in Guangzhou are about 3.424H.
(2) Daily power consumption of the load = 12.2AH
(3) The total charging current of the required solar modules = 1.05 × 12.2 × ÷ (3.424 × 0.85) = 5.9A
Here, the shortest design period between two consecutive rainy days is 20 days, 1.05 is the integrated loss factor of the solar cell module system, and 0.85 is the battery charging efficiency.
(4) Minimum total power of solar modules = 17.2 × 5.c = 102W
The standard battery pack with a peak output power of 110Wp and a single 55Wp should be used to ensure the normal operation of the streetlight system in most of the year.
2.2 Battery selection
The battery design capacity calculation is simpler than the peak wattage of the solar module.
According to the above calculation, the daily power consumption of the load is 12.2AH. In the case of full battery, you can work 7 rainy days in a row, plus the work of the first night, battery capacity:
12.2 × (7 + 1) = 97.6 (AH), the choice of two 12V100AH ​​batteries can meet the requirements.
2.3 Solar module bracket
2.3.1 Dip design
In order to get as much solar radiation as possible for a solar module in a year, we need to choose the best tilt angle for the solar module.
Discussions on the optimal tilt angle of solar modules have appeared in a number of academic journals in recent years. The area where the street lamp is used is the Guangzhou area. According to the data in the relevant literature [1], the solar cell module bracket inclination angle is 16 degrees.